Electrolysis equipment

Abstract

To suppress lowering of cell performance.SOLUTION: An electrolytic apparatus includes an electrolytic cell which includes: an anode; a cathode; a first flow passage plate having a first recess forming an anode flow passage which is provided so as to face the anode and forms an anode flow passage for allowing a first liquid to flow therein; a second flow passage plate having a second recess which is provided so as to face the cathode and forms a cathode flow passage for allowing the first liquid to flow therein; and a separator provided between the anode and the cathode. The second flow passage plate has an uneven surface in the inner surface of the second recess. Arithmetic average roughness of the uneven surface is 0.03 μm or more and 50 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to an electrolysis device. [Background technology]

[0002] In recent years, concerns have arisen about the depletion of fossil fuels such as oil and coal, and expectations are growing for sustainable renewable energy sources. Examples of renewable energy sources include solar cells and wind power. However, these energy sources have the challenge of making it difficult to provide a stable supply of electricity because the amount of power they generate depends on weather and natural conditions. For this reason, attempts have been made to stabilize the power supply by storing the electricity generated by renewable energy sources in storage batteries. However, storing electricity has problems such as the cost of storage batteries and the occurrence of losses during storage.

[0003] In response to these issues, attention is being paid to technologies that use electricity generated from renewable energy to perform water electrolysis to produce hydrogen (H2) from water, or electrochemically reduce carbon dioxide (CO2) and convert it into chemical substances (chemical energy) such as carbon compounds such as carbon monoxide (CO), formic acid (HCOOH), methanol (CH3OH), methane (CH4), acetic acid (CH3COOH), ethanol (C2H5OH), ethane (C2H6), and ethylene (C2H4). Storing these chemical substances in cylinders or tanks has the advantage of lowering energy storage costs and minimizing storage losses compared to storing electricity (electrical energy) in batteries.

[0004] For example, an electrolysis device using an Ag nanoparticle catalyst at the cathode, in which a cathode solution and CO2 gas are brought into contact with the cathode, and an anode solution is brought into contact with the anode, has been investigated. A specific configuration of the electrolysis device includes, for example, a cathode solution flow path arranged along one side of the cathode, a CO2 gas flow path arranged along the other side of the cathode, an anode solution flow path arranged along one side of the anode, and a separator arranged between the cathode solution flow path and the anode solution flow path. When an electrolysis device having such a configuration is used, for example, to pass a constant current between the cathode and the anode and perform a reaction to produce CO2 from CO2 for a long period of time, there is a problem of degradation of cell performance over time, such as a decrease in the amount of CO2 produced and an increase in cell voltage. Therefore, there is a need for a carbon dioxide electrolysis device that can suppress degradation of cell performance over time. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Zengcal Liu et al., Journal of CO2 Utilization, 15, p.50-56(2015) [Non-patent document 2] Sinchao Ma et al., Journal of The Electrochemical Society, 161(10), F1124-F1131(2014) Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to suppress the deterioration of the performance of the electrolysis cell. [Means for solving the problem]

[0007] The electrolysis device of the embodiment includes an electrolysis cell including an anode, a cathode, a first flow path plate facing the anode and having a first recess that forms an anode flow path through which a first liquid flows, a second flow path plate facing the cathode and having a second recess that forms a cathode flow path through which a first gas flows, and a separator provided between the anode and the cathode. The second flow path plate has an uneven surface on the inner surface of the second recess. The second flow plate has a first cathode catalyst layer including a first cathode catalyst provided on a textured surface. The arithmetic mean roughness of the uneven surface is 0.03 μm or more and 50 μm or less. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of an electrolysis device. [Figure 2] FIG. 2 is a cross-sectional view showing an electrolytic cell of the electrolytic device shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of an anode solution flow path in the electrolytic cell shown in FIG. [Figure 4] FIG. 3 is a diagram showing an example of a catholyte solution flow path in the electrolysis cell shown in FIG. [Figure 5] 3 is a diagram showing another example of a catholyte solution flow path in the electrolysis cell shown in FIG. 2. FIG. [Figure 6] FIG. 3 is a diagram showing an example of a cathode gas flow path in the electrolysis cell shown in FIG. [Figure 7] FIG. 3 is a diagram showing an example of a cathode in the electrolysis cell shown in FIG. 2. [Figure 8] FIG. 3 is a diagram showing another example of the cathode in the electrolysis cell shown in FIG. [Figure 9] FIG. 3 is a diagram schematically illustrating the reaction at the cathode in the electrolysis cell shown in FIG. 2. [Figure 10] FIG. 1 is a diagram showing the operation process of an electrolysis device. [Figure 11] 10 is a cross-sectional view showing a structural example of a flow path plate 28 having projections and recesses. FIG. [Figure 12] 10 is a cross-sectional view showing a structural example of a flow path plate 28 having projections and recesses. FIG. [Figure 13]10 is a schematic diagram showing an example of the shape of an uneven surface 291. FIG. [Figure 14] 3 is a cross-sectional view showing a structural example of a cathode flow path plate 28 having a cathode catalyst. FIG. [Figure 15] FIG. 10 is a diagram showing another example of the configuration of the electrolysis device. [Figure 16] FIG. 10 is a diagram showing another example of the configuration of the electrolysis device. [Figure 17] FIG. 10 is a diagram showing another example of the configuration of the electrolysis device. [Figure 18] FIG. 2 is a diagram showing the planar shape of a cathode flow channel in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In each embodiment shown below, substantially identical components are denoted by the same reference numerals, and some of their descriptions may be omitted. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each part, etc. may differ from the actual ones.

[0010] In this specification, unless otherwise specified, "connect" includes not only direct connection but also indirect connection.

[0011] Fig. 1 is a diagram showing an example of the configuration of an electrolysis apparatus. The electrolysis apparatus 1 shown in Fig. 1 includes an electrolytic cell 2, an anode solution supply system 100, a cathode solution supply system 200, a cathode gas supply system 300, a product collection system 400, a waste liquid collection system 500, and an anode solution adjustment system 600.

[0012] Fig. 2 is a cross-sectional view showing the configuration of the electrolytic cell in the electrolysis apparatus shown in Fig. 1. As shown in Fig. 2, the electrolytic cell 2 includes an anode part 10, a cathode part 20, and a separator 30.

[0013] The anode section 10 includes an anode 11 , an anode flow path 12 , and an anode current collector plate 13 .

[0014] The cathode section 20 has a cathode flow path 21, a cathode 22, a cathode flow path 23, and a cathode current collector plate 24. The cathode flow path 21 does not necessarily have to be provided.

[0015] The separator 30 is provided between the anode 11 and the cathode 22 and is arranged to separate the anode portion 10 and the cathode portion 20 .

[0016] The anode 11, anode flow channel 12, anode current collector 13, cathode flow channel 21, cathode 22, cathode flow channel 23, cathode current collector 24, and separator 30 may be stacked one on top of another. The electrolysis cell 2 is sandwiched between a pair of support plates (not shown), and further fastened with bolts or the like.

[0017] The anode 11 and the cathode 22 are connected to a power supply control unit 40 via a current introducing member. The power supply control unit 40 is not limited to a power source such as a normal power system power supply or a battery, and may also have a power source that supplies power generated by renewable energy such as solar cells or wind power generation. The power supply control unit 40 may have the above power source and a power controller that adjusts the output of the above power source to control the voltage between the anode 11 and the cathode 22.

[0018] The anode 11 is provided to oxidize a substance to be oxidized to generate an oxidation product. The anode 11 generates an oxidation reaction of water (HO) in an anode solution as an electrolyte, for example, to generate oxygen (O) and hydrogen ions (H + ) or hydroxide ions (OH -) to generate oxygen (O2) and water (HO). The anode 11 has a first surface 11a that contacts the separator 30 and a second surface 11b that faces the anode flow path 12. The first surface 11a of the anode 11 is in close contact with the separator 30. The anode flow path 12 faces the anode 11 and supplies an anode solution as an electrolyte to the anode 11. The anode flow path 12 is formed by pits (grooves / recesses) provided in a flow path plate 14 (anode flow path plate). The anode solution flows through the anode flow path 12 so as to contact the anode 11. The anode current collector plate 13 is in electrical contact with the surface of the flow path plate 14 that constitutes the anode flow path 12, opposite the anode 11.

[0019] The flow path plate 14 has a solution inlet and a solution outlet (not shown). The anode solution is introduced into and discharged from the flow path plate 14 by the anode solution supply system 100 via the solution inlet and solution outlet. The flow path plate 14 is preferably made of a material that has low chemical reactivity and high conductivity. Examples of such materials include metal materials such as Ti and SUS, and carbon. As shown in FIG. 3, the anode flow path 12 is preferably provided with a plurality of lands (protrusions) 14a. The lands 14a are provided for mechanical retention and electrical conduction.

[0020] The anode 11 oxidizes water (HO) to produce oxygen and hydrogen ions, or hydroxide ions (OH -The anode catalyst is preferably mainly composed of a catalytic material (anode catalyst material) capable of oxidizing ZnO (Fe-Zn) to produce water and oxygen and capable of reducing the overvoltage of such a reaction. Examples of such catalytic materials include metals such as platinum (Pt), palladium (Pd), and nickel (Ni), alloys and intermetallic compounds containing these metals, binary metal oxides such as manganese oxide (Mn-O), iridium oxide (Ir-O), nickel oxide (Ni-O), cobalt oxide (Co-O), iron oxide (Fe-O), tin oxide (Sn-O), indium oxide (In-O), ruthenium oxide (Ru-O), lithium oxide (Li-O), and lanthanum oxide (La-O), ternary metal oxides such as Ni-Co-O, Ni-Fe-O, La-Co-O, Ni-La-O, and Sr-Fe-O, quaternary metal oxides such as Pb-Ru-Ir-O and La-Sr-Co-O, and metal complexes such as Ru complexes and Fe complexes.

[0021] The anode 11 includes a substrate having a porous structure, such as a mesh material, punched material, porous material, or sintered metal fiber material, that allows the anode solution and ions to move between the separator 30 and the anode flow path 12. The substrate may be made of a metal material such as titanium (Ti), nickel (Ni), or iron (Fe), or an alloy containing at least one of these metals (e.g., SUS), or may be made of the above-mentioned anode catalyst material. When an oxide is used as the anode catalyst material, it is preferable to form a catalyst layer by adhering or laminating the anode catalyst material to the surface of a substrate made of the above-mentioned metal material. The anode catalyst material preferably contains nanoparticles, nanostructures, nanowires, etc., in order to enhance the oxidation reaction. A nanostructure is a structure in which nanoscale irregularities are formed on the surface of a catalyst material.

[0022] The cathode 22 is provided to reduce a target substance to generate a reduction product. The cathode 22 is an electrode (reduction electrode) that generates carbon compounds such as carbon monoxide (CO), methane (CH), ethane (C2H6), ethylene (C2H4), methanol (CH3OH), ethanol (C2H5OH), and ethylene glycol (C2H6O2) through a reduction reaction of carbon dioxide (CO2). In the cathode 22, a side reaction of generating hydrogen (H2) through a reduction reaction of water (H2O) may occur simultaneously with the reduction reaction of carbon dioxide (CO2). The cathode 22 has a first surface 22a facing the cathode flow channel 21 and a second surface 22b facing the cathode flow channel 23. The cathode flow path 21 is disposed between the cathode 22 and the separator 30 so that the cathode solution as the electrolyte comes into contact with the cathode 22 and the separator 30 .

[0023] The cathode flow path 21 faces the cathode 22 and is formed by a recess provided in a flow path plate 25 (cathode flow path plate). The flow path plate 25 is provided with a solution inlet (also simply referred to as an inlet) and a solution outlet (also simply referred to as an outlet), not shown. A cathode solution is introduced and discharged as an electrolyte by a cathode solution supply system 200 via the solution inlet and solution outlet. The cathode solution flows through the cathode flow path 21 so as to contact the cathode 22 and the separator 30. The flow path plate 25 that constitutes the cathode flow path 21 is preferably made of a material that is low in chemical reactivity and non-conductive. Examples of such materials include insulating resin materials such as acrylic resin, polyether ether ketone (PEEK), and fluororesin. The cathode flow path 21 may be omitted because it increases cell resistance.

[0024] In the cathode 22, a reduction reaction occurs mainly in the portion that comes into contact with the cathode solution. For this reason, it is preferable to use an opening with a large opening area for the cathode flow channel 21, as shown in FIG. 4. However, to improve mechanical support and electrical connectivity, lands (protrusions) 26 may be provided in the cathode flow channel 21, as shown in FIG. 5. The lands 26 of the cathode flow channel 21 are provided in the center of the cathode flow channel 21 and are held to the flow channel plate 25 by bridge portions 27 that are thinner than the lands 26 so as not to interfere with the flow of the cathode solution within the cathode flow channel 21. When lands 26 are provided in the cathode flow channel 21, it is preferable to have a small number of lands 26 in order to reduce cell resistance.

[0025] It is preferable that at least a portion of the land 26 overlaps the land 14a of the flow path plate 14. This ensures good electrical connection and reduces the electrical resistance of the electrolysis cell 2. It also ensures good contact between the separator 30 and the anode catalyst material and the cathode catalyst material, thereby not only reducing electrical resistance but also enabling efficient reactions. It is also preferable that at least a portion of the anode flow path 12 overlaps the land 26. This ensures good electrical connection and reduces the electrical resistance of the electrolysis cell 2. It also ensures good contact between the separator 30 and the anode catalyst material and the cathode catalyst material, thereby not only reducing electrical resistance but also enabling efficient reactions.

[0026] The cathode flow path 23 faces the cathode 22 and is formed by pits (grooves / recesses) provided in a flow path plate (cathode flow path plate) 28. The flow path plate 28, which constitutes the CO2 gas flow path through which gas containing carbon dioxide flows, is preferably made of a material with low chemical reactivity and high conductivity. Examples of such materials include metal materials such as Ti and SUS, and carbon. The flow path plates 14, 25, and 28 are provided with inlets and outlets for solutions and gases, as well as screw holes for fastening (not shown). Packing (not shown) is inserted in front of and behind each of the flow path plates 14, 25, and 28 as needed.

[0027] The flow path plate 28 is provided with a gas inlet and a gas outlet (not shown), through which CO gas or a gas containing CO (sometimes collectively referred to simply as CO gas) is introduced and discharged from the cathode gas supply system 300. The CO gas flows through the cathode flow path 23 so as to contact the cathode 22. As shown in FIG. 6, the cathode flow path 23 is preferably provided with a plurality of lands (protrusions) 29. The lands 29 are provided for mechanical retention and electrical conduction. The lands 29 are preferably provided alternately, so that the cathode flow path 23 meanders in the same manner as the anode flow path 12. The cathode current collector plate 24 is in electrical contact with the surface of the flow path plate 28 opposite the cathode 22.

[0028] In the electrolysis cell 2 of this embodiment, the provision of lands 14a, 29 in the anode flow path 12 and the cathode flow path 23 increases the contact area between the anode 11 and the flow path plate 14 that constitutes the anode flow path 12, and the contact area between the cathode 22 and the flow path plate 28 that constitutes the cathode flow path 23. Furthermore, the provision of a land 26 in the cathode flow path 21 increases the contact area between the cathode 22 and the flow path plate 25 that constitutes the cathode flow path 21. These features improve the mechanical retention of the electrolysis cell 2 while improving electrical conductivity between the anode current collector 13 and the cathode current collector 24, making it possible to improve the efficiency of the CO2 reduction reaction, etc.

[0029] As shown in FIG. 6, a hydrophilic region 280 may be formed on at least a portion of the surface 28a of the flow path plate 28. The hydrophilic region 280 has a lower contact angle with water than other regions of the surface 28a. This allows water to migrate from the rear half of the cathode flow path 23, which has a higher water content, to the front half. That is, water that has aggregated in the rear half of the cathode flow path 23, water that has migrated from the anode 11, and water generated by reactions can migrate to the flow path plate of the hydrophilic region 280. Therefore, in the front half of the cathode flow path 23, water that has migrated through the hydrophilic region 280 is vaporized by the cell temperature, humidifying the gas in the cathode flow path 23. In this way, providing the hydrophilic region 280 improves humidity uniformity within the cathode flow path 23 and enables humidification inside the cell without a humidifier. The hydrophilic region 280 has a contact angle with water that is greater than or equal to 0 degrees and less than 45 degrees. The contact angle is preferably 30 degrees or less, and more preferably 15 degrees or less. The hydrophilic region 280 may not be permeable to gases such as carbon dioxide, etc. The hydrophilic region 280 does not necessarily have to be provided.

[0030] The hydrophilic region 280 can be formed by, for example, roughening the surface 28a by adhering carbon particles or the like, coating the surface 28a with a hydrophilic conductive polymer such as polyacetylene, polythiophene, polyaniline, or polypyrrole, or by constructing the flow path plate 28 from a hydrophilic material.

[0031] As shown in FIG. 7, the cathode 22 has a gas diffusion layer 22A and a cathode catalyst layer 22B provided thereon. As shown in FIG. 8, a porous layer 22C that is denser than the gas diffusion layer 22A may be disposed between the gas diffusion layer 22A and the cathode catalyst layer 22B. As shown in FIG. 9, the gas diffusion layer 22A is disposed on the cathode flow channel 23 side, and the cathode catalyst layer 22B is disposed on the cathode flow channel 21 side. The cathode catalyst layer 22B may be embedded in the gas diffusion layer 22A. The cathode catalyst layer 22B preferably contains catalyst nanoparticles or catalyst nanostructures. The gas diffusion layer 22A is made of, for example, carbon paper or carbon cloth, and is treated to be water-repellent. The porous layer 22C is made of a porous material with a smaller pore size than the carbon paper or carbon cloth.

[0032] As shown in the schematic diagram of FIG. 9, cathode solution and ions are supplied to and discharged from the cathode flow channel 21 at the cathode catalyst layer 22B. Cathode gas is supplied to the gas diffusion layer 22A from the cathode flow channel 23, and products of the reduction reaction of the cathode gas are discharged. By subjecting the gas diffusion layer 22A to an appropriate water-repellent treatment, the cathode gas reaches the cathode catalyst layer 22B mainly by gas diffusion. The reduction reaction of CO2 and the reduction reaction of the carbon compounds produced thereby occur near the boundary between the gas diffusion layer 22A and the cathode catalyst layer 22B, or near the cathode catalyst layer 22B that has penetrated into the gas diffusion layer 22A. The gaseous products are mainly discharged from the cathode flow channel 23, and the liquid products are mainly discharged from the cathode flow channel 21.

[0033] The cathode catalyst layer 22B is preferably made of a catalyst material (cathode catalyst material) that can reduce carbon dioxide to produce carbon compounds and, if necessary, reduce the carbon compounds produced thereby to produce other carbon compounds, and that can reduce the overvoltage of such reactions. Examples of such materials include metals such as gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), titanium (Ti), cadmium (Cd), zinc (Zn), indium (In), gallium (Ga), lead (Pb), and tin (Sn), metal materials such as alloys and intermetallic compounds containing at least one of these metals, carbon materials such as carbon (C), graphene, CNTs (carbon nanotubes), fullerenes, and Ketjenblack, and metal complexes such as Ru complexes and Re complexes. The cathode catalyst layer 22B can be in various shapes such as a plate, mesh, wire, particle, porous, thin film, or island shape.

[0034] The cathode catalyst layer 22B may be made of a cathode catalyst material capable of reducing nitrogen to produce ammonia. Such a material may include molybdenum complexes. Examples of such materials include the molybdenum complexes (A) to (D) shown below.

[0035] A first example is a molybdenum complex having, as a PCP ligand (A), N,N-bis(dialkylphosphinomethyl)dihydrobenzimidazolidene (wherein the two alkyl groups may be the same or different, and at least one hydrogen atom on the benzene ring may be substituted with an alkyl group, an alkoxy group, or a halogen atom). A second example is a molybdenum complex having, as a PNP ligand (B), 2,6-bis(dialkylphosphinomethyl)pyridine (wherein the two alkyl groups may be the same or different, and at least one hydrogen atom on the pyridine ring may be substituted with an alkyl group, an alkoxy group, or a halogen atom). A third example is a molybdenum complex having, as the (C)PPP ligand, a bisbis(dialkylphosphinomethyl)arylphosphine (where the two alkyl groups may be the same or different). A fourth example is a molybdenum complex represented by (D) trans-Mo(N2)2(R1R2R3P)4 (where R1, R2, and R3 may be the same or different and are alkyl or aryl groups, and two R3s may be bonded to each other to form an alkylene chain).

[0036] In the molybdenum complexes described above, the alkyl group may be, for example, a linear or branched alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a structural isomer thereof, or a cyclic alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group. The alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. The alkoxy group may be, for example, a linear or branched alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a hexyloxy group, or a structural isomer thereof, or a cyclic alkoxy group such as a cyclopropoxy group, a cyclobutoxy group, a cyclopentoxy group, or a cyclohexyloxy group. The alkoxy group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0037] The molybdenum complex (A) may be, for example, a molybdenum complex represented by the following formula (A1).

[0038] [ka] (wherein R1 and R2 are alkyl groups which may be the same or different, X is an iodine atom, a bromine atom, or a chlorine atom, and at least one hydrogen atom on the benzene ring may be substituted with an alkyl group, an alkoxy group, or a halogen atom)

[0039] Examples of the alkyl group, alkoxy group, and halogen atom include those already exemplified. R1 and R2 are preferably bulky alkyl groups (e.g., tert-butyl or isopropyl). It is preferred that the hydrogen atoms on the benzene ring are unsubstituted or that the hydrogen atoms at the 5th and 6th positions are substituted with linear, cyclic, or branched alkyl groups having 1 to 12 carbon atoms.

[0040] Examples of the molybdenum complex (B) include molybdenum complexes represented by the following formulae (B1), (B2) and (B3).

[0041] [ka] (wherein R1 and R2 are alkyl groups which may be the same or different, X is an iodine atom, a bromine atom, or a chlorine atom, and at least one hydrogen atom on the pyridine ring may be substituted with an alkyl group, an alkoxy group, or a halogen atom)

[0042] Examples of the alkyl group, alkoxy group, and halogen atom include those already exemplified. R1 and R2 are preferably bulky alkyl groups (e.g., tert-butyl or isopropyl). It is preferred that the hydrogen atom on the pyridine ring is unsubstituted or that the hydrogen atom at position 4 is substituted with a linear, cyclic, or branched alkyl group having 1 to 12 carbon atoms.

[0043] The molybdenum complex (C) may be, for example, a molybdenum complex represented by the following formula (C1).

[0044] [ka] (wherein R1 and R2 are alkyl groups which may be the same or different, R3 is an aryl group, and X is an iodine atom, a bromine atom, or a chlorine atom)

[0045] Examples of the alkyl group include the same groups as those already exemplified. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and groups in which at least one of the cyclic hydrogen atoms is substituted with an alkyl group or a halogen atom. Examples of the alkyl group and the halogen atom include the same groups as those already exemplified. R1 and R2 are preferably bulky alkyl groups (e.g., tert-butyl group or isopropyl group). R3 is preferably, for example, a phenyl group.

[0046] Examples of the molybdenum complex (D) include molybdenum complexes represented by the following formulae (D1) and (D2).

[0047] [ka] (wherein R1, R2, and R3 are alkyl or aryl groups which may be the same or different, and n is 2 or 3).

[0048] Examples of the alkyl group and aryl group include those already exemplified. In formula (D1), it is preferred that R1 and R2 are aryl groups (e.g., phenyl groups) and R3 is an alkyl group having 1 to 4 carbon atoms (e.g., methyl group), or that R1 and R2 are alkyl groups having 1 to 4 carbon atoms (e.g., methyl group) and R3 is an aryl group (e.g., phenyl group). In formula (D2), it is preferred that R1 and R2 are aryl groups (e.g., phenyl groups) and n is 2.

[0049] The cathode catalyst material constituting the cathode catalyst layer 22B preferably comprises nanoparticles of the above-mentioned metal material, nanostructures of the metal material, nanowires of the metal material, or a composite in which nanoparticles of the above-mentioned metal material are supported on a carbon material such as carbon particles, carbon nanotubes, or graphene. By using catalyst nanoparticles, catalyst nanostructures, catalyst nanowires, catalyst nanosupport structures, etc. as the cathode catalyst material, the reaction efficiency of the carbon dioxide reduction reaction in the cathode 22 can be increased.

[0050] The separator 30 is provided between the anode 11 and the cathode 22. It is made of an ion exchange membrane or the like that allows ions to move between the anode 11 and the cathode 22 and is capable of separating the anode section 10 and the cathode section 20. As the ion exchange membrane, for example, a cation exchange membrane such as Nafion or Flemion, or an anion exchange membrane such as Neoceptor or Selemion can be used. As will be described later, alkaline solutions are used as the anode solution and cathode solution, and mainly hydroxide ions (OH - ), it is preferable that separator 30 be made of an anion exchange membrane. However, other materials than ion exchange membranes, such as glass filters, porous polymer membranes, and porous insulating materials, may also be used for separator 30 as long as they allow ions to move between anode 11 and cathode 22.

[0051] The anode solution and cathode solution as the electrolyte solution are preferably solutions containing at least water (H2O). Carbon dioxide (CO2) and nitrogen (N2) are supplied from the cathode flow path 23, so the cathode solution may or may not contain carbon dioxide (CO2) and nitrogen (N2). The same solution may be used for the anode solution and the cathode solution, or different solutions may be used. The solution containing H2O used as the anode solution and the cathode solution may be an aqueous solution containing any electrolyte. The aqueous solution containing an electrolyte may be, for example, a solution containing hydroxide ions (OH - ), hydrogen ions (H + ), potassium ions (K + ), sodium ions (Na + ), lithium ion (Li + ), chloride ions (Cl - ), bromide ion (Br - ), iodide ion (I - ), nitrate ions (NO3 - ), sulfate ions (SO4 2- ), phosphate ions (PO4 2- ), borate ion (BO3 3- ), and bicarbonate ions (HCO3 -In order to reduce the electrical resistance of the electrolyte solution, it is preferable to use an alkaline solution in which an electrolyte such as potassium hydroxide or sodium hydroxide is dissolved at a high concentration as the anode solution and the cathode solution.

[0052] The cathode solution contains cations such as imidazolium ions and pyridinium ions, and BF4 - and PF6 - Alternatively, an ionic liquid or an aqueous solution thereof may be used, which is a salt of an anion such as ethanolamine, imidazole, or pyridine and remains in a liquid state over a wide temperature range. Other examples of the cathode solution include solutions of amines such as ethanolamine, imidazole, and pyridine, or their aqueous solutions. The amine may be a primary amine, secondary amine, or tertiary amine.

[0053] The anode solution supply system 100 supplies the anode solution to the anode flow channel 12 as an electrolyte. The anode solution supply system 100 includes a pressure control unit 101, an anode solution tank 102, a flow rate control unit (pump) 103, a reference electrode 104, and a pressure gauge 105, and is configured to circulate the anode solution through the anode flow channel 12. The anode solution supply system 100 connects the inlet and outlet of the anode flow channel 12 via a flow channel 106. The anode solution supply system 100 circulates the anode solution so that it flows through the anode flow channel 12. The anode solution tank 102 contains a fluid containing the anode solution (also referred to as anode effluent) discharged from the outlet of the anode flow channel 12 and is connected to a gas component collector (not shown) that collects gas components such as oxygen (O2) contained in the circulating anode solution. The anode solution is introduced into the anode flow channel 12 with its flow rate and pressure controlled by the pressure control unit 101 and flow rate control unit 103.

[0054] The cathode solution supply system 200 supplies the cathode solution to the cathode flow channel 21. The cathode solution supply system 200 circulates the cathode solution so that the cathode solution flows through the cathode flow channel 21. The cathode solution supply system 200 has a pressure control unit 201, a cathode solution tank 202, a flow rate control unit (pump) 203, a reference electrode 204, and a pressure gauge 205, and is configured to circulate the cathode solution through the cathode flow channel 21. The cathode solution tank 202 is connected to a gas component collector 206 that collects gas components of reduction products such as carbon monoxide (CO) contained in the circulating cathode solution. The cathode solution is introduced into the cathode flow channel 21 with its flow rate and pressure controlled by the pressure control unit 201 and the flow rate control unit 203.

[0055] The cathode gas supply system 300 supplies cathode gas to the cathode flow path 23. The cathode gas supply system 300 includes a cathode gas supply source 301, a humidifier 311, a flow rate control unit 302, a pressure gauge 303, and a pressure control unit 304. The flow rate and pressure of the cathode gas are controlled by the flow rate control unit 302 and the pressure control unit 304, and the cathode gas is introduced into the cathode flow path 23.

[0056] The cathode gas supply source 301 is capable of supplying a cathode gas to the cathode flow channel 23. In the case of a carbon dioxide electrolysis device, the cathode gas supply source 301 is capable of supplying a cathode gas containing carbon dioxide gas to the cathode flow channel 23. In the case of a nitrogen electrolysis device, the cathode gas supply source 301 is capable of supplying a cathode gas containing nitrogen to the cathode flow channel 23. The cathode gas supply source 301 includes, for example, a tank that stores the cathode gas.

[0057] The humidifier 311 is capable of humidifying the cathode gas. The humidifier 311 has a tank that stores, for example, hot water. When the cathode gas passes through the tank, the cathode gas containing water vapor can be supplied to the cathode flow path 23. The cathode gas supply system 300 does not necessarily have to include the humidifier 311.

[0058] The product collection system 400 is connected to the cathode gas supply system 300 and collects products contained in the gas that has flowed through the cathode flow channel 23. The product collection system 400 has a gas-liquid separation unit 401 and a product collection unit 402. Reduction products such as CO and H2 contained in the fluid that has flowed through the cathode flow channel 23 are accumulated in the product collection unit 402 via the gas-liquid separation unit 401.

[0059] The waste liquid collection system 500 has a waste liquid collection tank 501 connected to the anode flow path 12 and the cathode flow path 21. The waste liquid of the anode solution and the cathode solution is collected in the waste liquid collection tank 501 by opening and closing valves (not shown). Operations such as opening and closing of the valves may be collectively controlled by a control system (not shown). The waste liquid of the anode solution and the cathode solution may be returned to the anode solution supply system 100 and the cathode solution supply system 200.

[0060] The operation of the electrolysis device 1 of this embodiment will be described. Here, an example of performing an electrolysis reaction of carbon dioxide will be described. First, as shown in Fig. 10, a start-up step S101 of the electrolysis device 1 is performed.

[0061] The start-up step S101 of the electrolysis device 1 involves the following operations. The anode solution supply system 100 controls the flow rate and pressure using a pressure control unit 101 and a flow rate control unit 103, and introduces the anode solution into the anode flow channel 12. The cathode solution supply system 200 controls the flow rate and pressure using a pressure control unit 201 and a flow rate control unit 203, and introduces the cathode solution into the cathode flow channel 21. The cathode gas supply system 300 controls the flow rate and pressure using a flow rate control unit 302 and a pressure control unit 304, and introduces the cathode gas into the cathode flow channel 23.

[0062] Next, the electrolysis operation step S102 is carried out. In the electrolysis operation step S102, the power supply control unit 40 of the electrolysis device 1 that has undergone the start-up step S101 starts applying an electrolysis voltage, and a voltage is applied between the anode 11 and the cathode 22 to supply a current. When a current flows between the anode 11 and the cathode 22, an oxidation reaction occurs near the anode 11 and a reduction reaction occurs near the cathode 22, as described below. Here, the case where carbon monoxide (CO) is produced as a carbon compound is mainly described, but the carbon compound as a reduction product of carbon dioxide is not limited to carbon monoxide, and may be other carbon compounds such as the organic compounds described above. Furthermore, the reaction process in the electrolysis cell 2 mainly involves the production of hydrogen ions (H + ) or mainly hydroxide ions (OH - ), but is not limited to any of these reaction processes.

[0063] First, it mainly oxidizes water (HO) to produce hydrogen ions (H + When a current is supplied between the anode 11 and the cathode 22 from the power supply control unit 40, an oxidation reaction of water (H2O) occurs at the anode 11 in contact with the anode solution. Specifically, as shown in the following formula (1), the H2O contained in the anode solution is oxidized to produce oxygen (O2) and hydrogen ions (H + ) is generated. 2H2O → 4H + +O2+4e - …(1)

[0064] H generated at anode 11 + The electrons (e - ) and H that has moved to the vicinity of cathode 22 + This causes a reduction reaction of carbon dioxide (CO2). Specifically, as shown in the following formula (2), CO2 supplied from the cathode flow channel 23 to the cathode 22 is reduced to produce CO. 2CO2+4H + +4e - → 2CO+2H2O …(2)

[0065] Next, carbon dioxide (CO2) is mainly reduced to hydroxide ions (OH - When a current is supplied between the anode 11 and the cathode 22 from the power supply control unit 40, water (HO) and carbon dioxide (CO) are reduced near the cathode 22 to produce carbon monoxide (CO) and hydroxide ions (OH), as shown in the following formula (3): - ) and hydroxide ions (OH - ) diffuses to the vicinity of the anode 11 and converts into hydroxide ions (OH - ) is oxidized to produce oxygen (O2). 2CO2+2H2O+4e - → 2CO+4OH - …(3) 4OH - → 2H2O+O2+4e - …(4)

[0066] Furthermore, when nitrogen, a target substance to be reduced, is reduced to produce ammonia (NH3), a reduction product, water or hydroxide ions are electrochemically oxidized near the anode 111 according to the following formula (5) or formula (6), producing oxygen. Near the cathode 121, nitrogen is reduced according to the following formula (7) or formula (8), producing ammonia. 3H2O → 3 / 2O2+6H + +6e - …(5) 6OH - → 3 / 2O2+3H2O+6e - …(6) N2+6H2O+6e - → 2NH3+6OH - …(7) N2+6H + +6e - → 2NH3…(8)

[0067] Next, an electrolysis stopping step S103 is carried out. In the electrolysis stopping step S103, it is determined whether or not to continue the electrolysis operation, and if the electrolysis operation is to be stopped, the application of the electrolysis voltage by the power supply control unit 40 of the electrolysis device 1 is stopped. The electrolysis operation is stopped, for example, when the electrolysis efficiency of the electrolysis cell 2 falls below a reference value.

[0068] Next, the shut-down step S104 of the electrolysis device 1 carries out the following operations. The anode solution supply system 100 controls the pressure control unit 101 and the flow rate control unit 103 to stop the introduction of the anode solution into the anode flow channel 12. The cathode solution supply system 200 controls the pressure control unit 201 and the flow rate control unit 203 to stop the introduction of the cathode solution into the cathode flow channel 21. The cathode gas supply system 300 controls the flow rate control unit 302 and the pressure control unit 304 to stop the introduction of the cathode gas into the cathode flow channel 23.

[0069] During electrolysis, if the cathode catalyst peels off from the cathode 22, it is discharged from the electrolysis cell 2 via the cathode flow path 23, reducing the amount of cathode catalyst in the cathode 22, which causes a decrease in electrolysis efficiency and cell performance.

[0070] Therefore, the electrolysis device of the embodiment forms irregularities on the surface 28a that can capture the cathode catalyst. The cathode catalyst captured by the irregularities on the surface 28a can cause a reduction reaction, thereby preventing a decrease in cell performance.

[0071] 11 and 12 are cross-sectional schematic diagrams showing an example structure of an uneven flow path plate 28. The surface 28a of the flow path plate 28 on the cathode 22 side has an uneven surface 291. The uneven surface 291 shown in FIG. 11 is provided on the entire surface 28a of the flow path plate 28.

[0072] FIG. 13 is a schematic diagram showing an example of the shape of the uneven surface 291. FIG. 13 is an enlarged view of a portion of the flow path plate 28 shown in FIG. 11. The surface roughness of the uneven surface 291 (the width of each unevenness) is preferably 0.03 μm or more and 50 μm or less. Considering the particle size of the cathode catalyst, a surface roughness of 0.03 μm or more and 1 μm or less is suitable for capturing and adsorbing the cathode catalyst by the uneven surface 291. When the cathode catalyst is supported on a carrier, the surface roughness of the uneven surface 291 is preferably 0.03 μm or more, which is the particle size of the carrier, and may be 50 μm or less, which is the diameter of the carrier aggregate, which is suitable for capturing and adsorbing the catalyst carrier. Generally, the smaller the aggregate, the better, and carrier aggregates with a particle size of 10 μm or less are preferred, so the unevenness is also preferably 10 μm or less. The surface roughness is preferably 0.05 μm or more, and more preferably 0.1 μm or more. The surface roughness is defined by a value measured by an analytical method using, for example, a laser microscope, Talystep, Surftest, or a scanning electron microscope (SEM).

[0073] The average roughness (arithmetic mean roughness) of the uneven surface 291 is preferably 10 nm to 30 μm, more preferably 1 μm to 10 μm, and even more preferably 3 μm to 10 μm. The maximum height of the hydrophilic region 280 is preferably 1 μm to 50 μm.

[0074] The uneven surface 291 may be provided on the entire flow path plate 28. This can be achieved, for example, by forming the flow path plate 28 from a porous body. The average pore size of the porous body is preferably 0.1 μm or more and 10 μm or less. The porosity of the hydrophilic porous body is preferably 30% or more and 80% or less. The average pore size and porosity of the porous body can be measured by analytical methods such as a laser microscope, Talystep, or Surftest.

[0075] By forming the uneven surface 291 having the above surface roughness, the cathode catalyst or a carrier carrying the cathode catalyst can be captured in the cathode flow channel 23. When the cathode catalyst peels off the surface of the cathode 22, the amount of catalyst decreases, resulting in a decline in cell performance. Therefore, by capturing the peeled cathode catalyst or the carrier carrying the cathode catalyst on the uneven surface 291, a reduction reaction occurs in part on the cathode flow channel 23, and a decline in the performance of the electrolysis cell 2 can be suppressed.

[0076] By forming the uneven surface 291 in the cathode flow channel 23, the phenomenon of carbonate precipitation occurring during electrolysis, for example, when cations, which are components of the electrolyte, react with carbon dioxide gas, can be suppressed in the cathode flow channel 23.

[0077] The uneven surface 291 may be provided on only a part of the surface 28a of the flow path plate 28. The uneven surface 291 shown in Fig. 12 is provided on the inner side and inner bottom surface of the recess that forms the cathode flow path 23, and is not provided on the land 29. The surface roughness of the surface of the portion of the surface 28a of the flow path plate 28 where the uneven surface 291 is not provided is smaller than the surface roughness of the uneven surface 291.

[0078] As described above, the uneven surface 291 may be formed on the entire flow path plate 28 from the viewpoint of processability. However, from the viewpoint of increased work and costs associated with processing, the uneven surface 291 may be formed only on the portion of the flow path plate 28 corresponding to the cathode flow path 23. Furthermore, when the uneven surface 291 is formed on the entire flow path plate 28, increasing the size of the unevenness of the uneven surface 291 is undesirable because it makes it easier for the cathode gas to permeate through the lands 29 in contact with the cathode catalyst, preventing the cathode gas from flowing along the cathode flow path 23 and causing the cathode gas to flow by taking a shortcut through the cathode flow path 23. Furthermore, from the viewpoint of reactivity and capture of the cathode catalyst, the uneven surface 291 may be provided only on the rear half of the cathode flow path 23, or the surface roughness of the uneven surface 291 on the rear half of the cathode flow path 23 may be varied. That is, the surface roughness of the rear half of the cathode flow path 23 is preferably greater than the surface roughness of the front half of the cathode flow path 23. This can promote capture of the cathode catalyst layer 292 or the carrier supporting the cathode catalyst layer 292 in the rear half of the cathode flow channel 23. The front half of the cathode flow channel 23 is a portion that is closer to the inlet IN than to the outlet OUT along the length of the cathode flow channel 23. The rear half of the cathode flow channel 23 is a portion that is closer to the outlet OUT than to the inlet IN along the length of the cathode flow channel 23.

[0079] The uneven surface 291 can be formed, for example, by machining a metal plate used to form the flow path plate 28. It is efficient and preferable to perform machining at the same time as forming recesses by cutting. Alternatively, the uneven surface 291 may be formed in advance by etching or the like on the metal plate to be pressed, or the uneven surface 291 may be formed during pressing. The uneven surface 291 can also be formed by methods such as roughening the surface by adhering carbon particles or the like, or by coating the surface of the flow path plate 28 with a hydrophilic conductive polymer such as polyacetylene, polythiophene, polyaniline, or polypyrrole to form the uneven surface 291. The uneven surface 291 can also be formed by etching the surface of the metal plate.

[0080] The uneven surface 291 may be formed not only by microfabrication, but also by forming a large uneven surface 291 to increase the surface area of ​​the cathode flow channel 23. For example, a conductive member with an uneven surface 291 of approximately 0.2 mm diameter may be provided in a flow channel with a width and depth of 1 mm, or a cylindrical member with a diameter of approximately 0.2 mm and a depth of 1 mm may be provided in the flow channel. This type of shaping is particularly preferable in the rear half of the cathode flow channel 23, as it improves the ability to capture exfoliated cathode catalyst and improves reaction efficiency in the rear half of the cathode flow channel 23, where reaction conditions are more severe, thereby improving electrolysis efficiency throughout the cell. Alternatively, a conductive wire mesh member may be provided on the surface of the cathode flow channel 23, and a finely uneven surface 291 may be provided on the surface of the wire mesh member to capture the cathode catalyst. Furthermore, a honeycomb-shaped conductive member may be provided on the flow channel to reduce pressure loss in the cathode flow channel 23 and improve the ability to capture exfoliated catalyst.

[0081] Furthermore, the cathode flow channel plate 28 may have a cathode catalyst pre-loaded thereon. Fig. 14 is a cross-sectional schematic diagram showing an example of the structure of the cathode flow channel plate 28 having a cathode catalyst. The flow channel plate 28 shown in Fig. 14 has a cathode catalyst layer 292 containing a cathode catalyst loaded on an uneven surface 291 of the surface 28a.

[0082] The cathode catalyst layer 292 is preferably made of a catalyst material (cathode catalyst material) that can reduce carbon dioxide to produce carbon compounds, and if necessary, can reduce the carbon compounds produced thereby to produce other carbon compounds, and that can reduce the overvoltage of such reactions. Examples of such materials include metals such as gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), titanium (Ti), cadmium (Cd), zinc (Zn), indium (In), gallium (Ga), lead (Pb), and tin (Sn), metal materials such as alloys and intermetallic compounds containing at least one of these metals, carbon materials such as carbon (C), graphene, CNTs (carbon nanotubes), fullerenes, and Ketjenblack, and metal complexes such as Ru complexes and Re complexes. Without being limited thereto, the cathode catalyst layer 292 may use a cathode catalyst material capable of reducing nitrogen to produce ammonia, such as the molybdenum complexes described above.

[0083] The cathode catalyst layer 292 is formed, for example, by attaching particulate cathode catalyst to the surface 28a including the uneven surface 291. The attachment method can be spraying it onto the flow path, or mixing it with an organic adhesive to facilitate adhesion to the particulate cathode catalyst and then spraying it onto the surface 28a. Examples of adhesives include organic materials such as polyvinyl alcohol (PVA). It is also preferable to use an ion exchange resin, such as Nafion, to promote ion migration.

[0084] The cathode catalyst layer 292 may be attached to the entire surface 28a, or may be attached only to the recesses that form the cathode flow channel 23. This allows the effect to be achieved with a small amount of cathode catalyst. One method for supporting the cathode catalyst only in the recesses is to circulate ink containing a mixture of the cathode catalyst and an ion exchange resin through the cathode flow channel 23, and then perform a drying process or a heating process to form the cathode catalyst only on the inner side and inner bottom surfaces of the recesses that form the cathode flow channel 23.

[0085] In the rear half of the cathode flow channel 23, the CO2 concentration in particular decreases with the reaction, and the concentration of the produced gas increases, so the reaction efficiency decreases. Therefore, more effective results can be obtained by previously loading a larger amount of cathode catalyst in the rear half of the cathode flow channel 23. In other words, the amount of cathode catalyst loaded in the cathode catalyst layer 292 in the rear half of the cathode flow channel 23 is preferably greater than the amount of cathode catalyst loaded in the cathode catalyst layer 292 in the front half of the cathode flow channel 23.

[0086] The cathode catalyst provided in the cathode catalyst layer 292 may be the same material as the cathode catalyst provided in the cathode catalyst layer 22B, but may be different. Because the reaction conditions differ between the surface of the cathode catalyst layer 22B and the surface 28a, it is preferable to change the composition of the cathode catalyst layer. For example, a lower ionomer content in the cathode catalyst layer 292 than in the cathode catalyst layer 22B is preferable because it can suppress flooding (a phenomenon in which water inhibits gas diffusion) caused by liquid retention on the surface 28a. This effect can be further enhanced by including the hydrophilic region 280. Similarly, because the reaction conditions differ between the surface of the cathode catalyst layer 22B and the surface 28a, it is preferable to make the density, amount, and shape of the cathode catalyst provided in the attached cathode catalyst layer 292 different from those of the cathode catalyst provided in the cathode catalyst layer 22B. From the standpoint of the effect and cost of the attached cathode catalyst layer 292, the amount of cathode catalyst on surface 28a is overwhelmingly more efficient, so it is preferable that the amount of cathode catalyst in cathode catalyst layer 292 be less than the amount of cathode catalyst in cathode catalyst layer 22B, and is preferably at least 1 / 10 or less of the amount of cathode catalyst in cathode catalyst layer 22B. Also, because the density of the cathode catalyst on surface 28a is overwhelmingly more efficient, it is preferable that the density of the cathode catalyst on surface 28a be higher than the density of the cathode catalyst in cathode catalyst layer 22B, reduce the amount, and allow the reaction to occur only in cathode flow channel 23. This is because, considering the movement of ions between anode 11 and cathode 22, the reaction on cathode flow channel 23 is inefficient due to the large amount of ion movement, and forming a thick cathode catalyst layer 292 makes ion movement more difficult, so a thin layer is preferable. Similarly, the shape of the cathode catalyst layer 292 is such that, because ion migration is smooth on the surface of the cathode catalyst layer 22B, a cathode flow path 23 with a relatively high porosity and high gas diffusivity is preferable, but a low porosity is preferable on the cathode flow path 23, in which case gas diffusibility deteriorates, so the cathode catalyst layer 292 is preferably thinner than the cathode catalyst layer 22B. This is because a thin layer reduces the amount of ion migration from the anode section 10 and also improves gas flow by increasing the cross-sectional area of ​​the flow path.

[0087] The spatial density of the cathode catalyst layer 292 is preferably lower, i.e., sparser, than that of the cathode catalyst layer 22B, and the thickness is also preferably thinner. The cathode catalyst layer 292 preferably has a thickness at least 1 / 10 of that of the cathode catalyst layer 22B.

[0088] It is preferable that the amount of ionomer as an ion exchange resin is less on surface 28a than on the surface of cathode catalyst layer 22B. This is because the reaction takes place on the cathode catalyst immediately separated from anode 11 by a membrane, and the ions that did not react on cathode catalyst layer 22B react with carbon dioxide, so the reaction amount is very small, and it is preferable that the amount of ionomer is small and the proportion of metal particles and the like of the cathode catalyst, which mainly react, is high.

[0089] It is preferable that the amount of cathode catalyst be greater in the latter half of the cathode flow channel 23 than in the former half of the cathode flow channel 23. This is because the concentration of the substance to be reduced in the raw material components decreases in the latter half of the cathode flow channel 23, and in order to carry out the reaction in a state where the product concentration is high, it is preferable that the amount supported be greater in the latter half.

[0090] As described above, in the reaction process at the cathode 22 during electrolysis, the reduction reaction is thought to occur near the boundary between the gas diffusion layer 22A and the cathode catalyst layer 22B. If the cathode solution flowing through the cathode flow path 21 penetrates into the gas diffusion layer 22A or if the cathode catalyst layer 22B becomes overhydrated, problems such as a decrease in the amount of reduction product produced by the reduction reaction and an increase in cell voltage can occur. Such a decrease in cell performance of the electrolysis cell 2 can also be caused by uneven distribution of ions and residual gases near the anode 11 and cathode 22, excess moisture in the cathode catalyst layer 22B, electrolyte precipitation in the cathode 22 and anode 11, and electrolyte precipitation in the anode flow path 12 and cathode flow path 21.

[0091] Furthermore, electrolysis can cause salts to precipitate in the cathode flow channel 21 and gas diffusion layer 22A, resulting in clogging of the flow channel and reduced gas diffusibility, which can degrade cell performance. This occurs because ions move between the anode 11 and cathode 22 via the separator 30 and ion exchange membrane and react with gas components. For example, if a potassium hydroxide solution is used as the anode solution and carbon dioxide gas is used as the cathode gas, potassium ions move from the anode section 10 to the cathode section 20 and react with carbon dioxide to produce salts such as potassium bicarbonate and potassium carbonate. If the salts are below their solubility in the cathode flow channel 21 and gas diffusion layer 22A, they will precipitate in the cathode flow channel 21 and gas diffusion layer 22A. Clogging of the flow channel can impede uniform gas flow throughout the cell, resulting in reduced cell performance.

[0092] Salt deposits in the cathode flow channel 23 more easily in the first half than in the second half. This increases the moisture content in the gas diffusion layer, reducing the carbon dioxide diffusivity and cell performance. This phenomenon is called flooding.

[0093] On the other hand, if the salt is below the solubility, salt precipitation can be prevented by providing a humidifier 311 to humidify the cathode gas and increase the water content. Furthermore, supplying a rinse liquid from upstream of the cathode flow path 21 or 23 dissolves the salt, preventing blockage of the flow path due to precipitation, and suppressing performance degradation. For the entire electrolysis device 1, it is preferable to minimize the discharge of water from the system and circulate the electrolyte within the system.

[0094] The gas diffusion layer 22A has water repellency to improve gas diffusion, and because water movement in the cathode catalyst layer 22B is poor, it is effective to move water using the hydrophilic region 280. This also makes the humidification conditions inside the cell uniform, improving the surface uniformity of the reaction. In particular, when an electrolyte membrane is used, a uniform humidification environment prevents the membrane from drying out, optimizes ion movement at every location within the cell surface, and improves the surface uniformity of the reaction.

[0095] Electrolyte components may move from the anode section 10 to the cathode section 20 and be discharged from the outlet of the cathode flow path 23 of the electrolytic cell 2. For this reason, the outlet of the cathode flow path 23 is connected to a gas-liquid separator 401 to separate the discharged water and gas. The electrolyte components discharged from the outlet of the cathode flow path 23 are separated by the gas-liquid separator 401 and stored as a liquid.

[0096] As electrolyte components move from the anode section 10 to the cathode section 20, the concentration and amount of the electrolyte components in the anode solution gradually decrease in the anode solution supply system 100. This reduces the cell resistance and hinders ion movement, causing a decrease in cell performance.

[0097] In response to this, by providing an anode solution adjustment system connected to the outlet of the cathode flow path 23, a refresh operation can be performed in which the liquid containing the electrolyte component separated by the gas-liquid separator 401 is returned to the anode electrolyte circulation path of the anode solution supply system 100.

[0098] Figure 15 is a schematic diagram showing another configuration example of the electrolysis device 1. The electrolysis device 1 shown in Figure 15 differs from the electrolysis device 1 shown in Figure 1 in that it further includes an anode solution adjustment system 600.

[0099] The anode solution adjustment system 600 is provided midway along the flow path 31 that connects the product collection system 400 and the waste liquid collection system 500. The flow path 31 is formed, for example, by piping. The anode solution adjustment system 600 has a valve 601 and a filter 602. The filter 602 can collect the cathode catalyst from the electrolyte separated by the gas-liquid separation unit 401. For example, the anode solution adjustment system 600 can open the valve 601 and send the electrolyte separated by the gas-liquid separation unit 401 to the waste liquid collection tank 501 via the filter 602.

[0100] This operation changes the amount of circulating electrolyte because the amount of water in each gas-liquid separator changes depending on parameters such as the electrolyte temperature and the temperature of the gas discharged from the cathode flow path 23. Therefore, in order to adjust the electrolyte, pure water or a high-concentration electrolyte may be supplied from the outside to adjust the concentration.

[0101] When the refresh operation causes the peeled cathode catalyst or the carrier carrying the cathode catalyst to be discharged through the cathode flow path 23, the cathode catalyst gets mixed into the anode solution supply system 100, causing side reactions or interfering with the reaction, thereby reducing cell performance.

[0102] In response to this, by forming the uneven surface 291 and capturing the exfoliated cathode catalyst or the carrier carrying the cathode catalyst by the uneven surface 291, it is possible to prevent the cathode catalyst from being mixed into the anode solution supply system 100.

[0103] Even when measures to capture the exfoliated cathode catalyst are taken, the cathode catalyst may still be discharged from the cathode flow path 23. Therefore, by installing a filter 602 in the flow path that returns the liquid containing the electrolyte solution components to the anode solution supply system 100 to capture the cathode catalyst, even if the cathode catalyst is mixed with the electrolyte solution components, pressure loss in the cathode flow path 23 can be reduced and the cathode catalyst can be prevented from being mixed into the anode solution supply system 100. Furthermore, since the cathode catalyst is mixed into the anode solution, the effect of impurities on the oxidation reaction is reduced and efficiency is maintained. Furthermore, the release of catalyst particles to the outside can be suppressed, and the cathode catalyst can be recovered from the filter 500. Note that, because the cathode catalyst particles that peel off from the cathode flow path 23 are conductive, when the electrolysis cells 2 are stacked, current flows between the flow paths via the catalyst particles, resulting in a decrease in reaction efficiency. Therefore, it is preferable that the catalyst particles that peel off within the cell be as thin as possible.

[0104] If filter 602 is located between the outlet of cathode flow channel 23 and gas-liquid separation unit 401, there is an advantage in that exfoliated catalyst does not get mixed into the liquid after gas-liquid separation, but on the other hand, pressure loss occurs in the filter, so control of the cathode pressure must be considered. If filter 602 is provided between the liquid tank of gas-liquid separation unit 401 and the waste liquid collection tank 501 or the anode flow channel 12, there is no need to consider pressure loss in filter 602, but exfoliated catalyst particles may get mixed into the gas released from gas-liquid separation unit 401, and if a filter or the like is required, this will also cause pressure loss. However, if filter 602 captures exfoliated cathode catalyst, the pressure loss is less for gas, so the pressure loss is less than if filter 602 is located between the outlet of cathode flow channel 23 and gas-liquid separation unit 401.

[0105] If the separated liquid contains water, the liquid can be returned to the humidifier 311 to produce water for humidifying the cathode gas. Fig. 16 is a schematic diagram showing another configuration example of the electrolysis device 1. The electrolysis device 1 shown in Fig. 16 differs from the electrolysis device 1 shown in Fig. 1 in that it further comprises a flow path 32 that connects the gas-liquid separation section 401 and the inlet of the cathode flow path 23.

[0106] Returning the liquid to the humidifier 311 reduces the amount of water discharged outside the system due to water vapor in the exhaust gas from the cathode flow path 23 and the oxygen gas from the anode flow path 12. The source water is water produced by the reaction in the humidifier 311 and water formed by the movement of the electrolyte to the cathode section 20. Because the amount of water lost in the humidifier 311 is rapid, it is necessary to supply water from an external source.

[0107] When the liquid captured at the outlet of the cathode flow path 23 is used as humidifying water for the humidifier 311, providing the humidifier 311 with a filter can prevent impurities such as catalyst particles from entering the humidifier 311. The filter can be given the function of capturing not only peeled cathode catalyst but also gaskets and separators 30 that have washed away from the electrolytic cell 2, carbon particles that have peeled off from the gas diffusion layer 22A, and the like. This filter can prevent impurities from entering the anode solution and the humidifier 311. The filter may also be given the function of capturing ionic components eluted from the electrolytic cell 2, piping, and the like. Metal ion components from the piping and cell can cause a decrease in cell performance when a catalyst or separator membrane, particularly an electrolyte membrane, is used, so it is preferable to capture the ions.

[0108] If the separated liquid contains electrolyte components, the electrolyte components may be mixed into the cathode gas via the humidifier 311, which may inhibit the salt precipitation prevention effect. In addition, the humidifier 311 must also be manufactured to specifications that are resistant to the electrolyte components, which is undesirable as it increases costs.

[0109] Therefore, gas-liquid separation of the oxygen gas and the electrolyte solution is performed at the outlet of the anode flow channel 12. The water vapor in the oxygen gas is cooled, and the water obtained by gas-liquid separation is used as water for the humidifier upstream of the cathode. This is preferable because the water obtained by cooling the water vapor in the oxygen gas and performing gas-liquid separation is distilled water, and the concentration of the electrolyte solution components is extremely low, maintaining the salt deposition prevention effect and eliminating the need to consider the resistance of the electrolyte solution components in the humidifier 311.

[0110] The separated cathode catalyst is accumulated in a tank that stores the liquid separated by the gas-liquid separator 401. Meanwhile, the cell performance of the electrolysis cell 2 declines due to a decrease in the amount of catalyst. Therefore, by returning the accumulated cathode catalyst from the inlet of the cathode flow path 23, the catalyst adheres to the cathode catalyst layer 22B and the cathode flow path 23, making it possible to replenish the lost catalyst in the cathode catalyst layer 22B. This suppresses cell performance degradation and enables the electrolysis device 1 to operate efficiently for a long period of time. Furthermore, the uneven surface 291 facilitates adhesion of the cathode catalyst, thereby improving the suppression of cell performance degradation. As shown in FIG. 17 , an anode solution adjustment system 600 is preferably provided, which recovers catalyst from the filter 602 and returns catalyst from the upstream of the cathode flow path 23. The filter 602 and the inlet of the cathode flow path 23 are preferably connected by a flow path 33. When a certain amount of catalyst has accumulated, the lost catalyst in the cathode catalyst layer 22B can be replenished while the reaction is proceeding. Note that if a filter 602 is provided directly at the outlet of the cathode flow channel 23, the pressure loss throughout the cathode flow channel 23 will increase, potentially reducing the efficiency of the system. The description of the anode solution adjustment system 600 shown in Fig. 15 can be used as appropriate for other explanations of the anode solution adjustment system 600. The flow channels 32 and 33 are formed, for example, by piping.

[0111] The electrolysis device of the embodiment is not limited to a carbon dioxide electrolysis device, and may be, for example, a nitrogen electrolysis device. In the case of a nitrogen electrolysis device, nitrogen (N2) gas is supplied from the cathode gas supply source 301 to the cathode flow path 23, and the nitrogen gas is reduced by the cathode 22 to produce ammonia. The configuration of the carbon dioxide electrolysis device can be used as appropriate for other configurations of the nitrogen electrolysis device. [Example]

[0112] Example 1 The electrolysis device shown in Figure 1 was assembled to investigate the electrolysis performance of carbon dioxide. First, a cathode was prepared by coating carbon particles carrying gold nanoparticles on carbon paper with a porous layer, using the following procedure. A coating solution was prepared by mixing carbon particles carrying gold nanoparticles with pure water, Nafion solution, and ethylene glycol. The average diameter of the gold nanoparticles was 8.7 nm, and the loading amount was 18.9 mass%. This coating solution was filled into an airbrush and spray-coated onto the carbon paper with a porous layer using nitrogen gas. After coating, the carbon paper was washed with running pure water for 30 minutes and then immersed in hydrogen peroxide to oxidize and remove organic substances such as ethylene glycol. This was cut into a 2 x 2 cm piece to prepare the cathode. The amount of Au coated was approximately 0.2 mg / cm, based on the combined amount of gold nanoparticles and carbon particles in the coating solution. 2 The anode was an electrode made of Ti nonwoven fabric coated with IrO2 nanoparticles as a catalyst. An IrO2 / Ti mesh cut into 2 x 2 cm was used as the anode. The catalyst area was 2 cm x 2 cm = 4 cm 2 The area of ​​the cathode catalyst layer 22B in contact with the surface 28a was 4 cm 2 The distance between the inlet IN and the outlet OUT is 0.8 cm, and the distance between the inlet IN and the outlet OUT / √√area of ​​the cathode catalyst layer 22B=0.2.

[0113] As shown in FIG. 2, the electrolysis cell 2 was fabricated by stacking, from top to bottom, a cathode current collector 24, a cathode flow path 23 (flow path plate 28), a cathode 22, a cathode flow path 21 (flow path plate 25), a separator 30, an anode 11, an anode flow path 12, and an anode current collector 13, sandwiching them between support plates (not shown), and fastening them with bolts. An anion exchange membrane (product name: Selemion) was used for the separator 30. The IrO2 / Ti mesh of the anode 11 was in close contact with the anion exchange membrane. The thickness of the cathode flow path 23 was 1 mm. The flow path plate 28 was made of titanium. The cathode flow path 23 was fabricated by cutting the flow path plate 28. The planar shape of the cathode flow path 23 is shown in FIG. 18. The planar shape of the cathode flow path 23 is serpentine, with four folds. The cathode flow path 23 has four pairs of parallel flow path regions connected in parallel on the surface 28a. The width of the cathode flow path 23 is 1 mm. The depth of the cathode flow path 23 in the thickness direction of the flow path plate 28 is 1 mm. The width of the land 29 is 1 mm.

[0114] The contact surface of the flow path plate 28 with the gas diffusion layer 22A has been subjected to surface processing to form an uneven surface 291 having a surface roughness (width of each unevenness) of 30 nm to 10 μm. The average roughness (arithmetic mean roughness) of the uneven surface 291 was approximately 0.3±0.1 μm.

[0115] The electrolysis device 1 shown in FIG. 1 was assembled using the electrolysis cell 2 described above, and the electrolysis device was operated under the following conditions. The cell was heated to 50°C, and humidified CO2 gas at 45°C was supplied to the cathode flow path 23 of the electrolysis cell 2 at 20 sccm, and an aqueous potassium bicarbonate solution (concentration 1 M KHCO3) was supplied to the anode flow path 12 at a flow rate of 20 mL / min. Next, a constant current of 800 mA was applied between the anode 11 and the cathode 22 at a constant current density of 200 mA / cm by controlling the voltage using the power supply control unit 40. 2The CO2 electrolysis reaction was carried out for a specified time by flowing water, and the cell voltage was measured and collected by the data collection and control unit. Furthermore, a portion of the gas output from the cathode flow path 23 was collected, and the amounts of CO gas produced by the CO2 reduction reaction and H2 gas produced by the water reduction reaction were analyzed by gas chromatography. The data collection and control unit calculated and collected the partial current density of CO or H2 from the amount of gas produced, as well as the Faraday efficiency, which is the ratio of the total current density to the partial current density. The results are shown in Table 1.

[0116] Example 2 A carbon dioxide electrolysis device was assembled in the same manner as in Example 1, and the carbon dioxide electrolysis performance was investigated. Unlike in Example 1, hydrophilic carbon powder was attached to only the inner side and inner bottom surfaces of the recesses that form the cathode flow channels 23 on the surface 28a of the flow channel plate 28 to form hydrophilic regions 280. The hydrophilic regions 280 had a surface roughness of 20 nm or more and 5 μm or less, with an average roughness of approximately 3±1 μm.

[0117] Example 3 Using the flow path of Example 2, a glass container with a volume of 50 cc was installed at the outlet of the cathode flow path 23, and gas-liquid separation was performed. The accumulated liquid was passed through a filter with a mesh size of 0.01 μm and returned to the 1 L anode solution tank 102 by a pump. The fluid discharged from the anode flow path 12 was separated into gas and liquid in the gas-liquid separator 401 and the anode solution tank 102, the released gas was cooled, the water vapor was captured, and distilled water was stored in a 100 ml glass tank. When a certain amount of distilled water had accumulated, the distilled water was returned to the humidifier 311 upstream of the cathode flow path, and the carbon dioxide electrolysis performance was examined in the same manner as in Example 2.

[0118] Example 4 A carbon dioxide electrolysis device was assembled and its carbon dioxide electrolysis performance was investigated in the same manner as in Example 3. As in Example 2, a cathode catalyst powder and an ionomer were attached to the inner surface and inner bottom surface of the recess forming the cathode flow channel 23 to a thickness of 1 μm under the same conditions as for the cathode catalyst layer 22B, and a reaction was carried out.

[0119] (Comparative Example 1) A carbon dioxide electrolysis device was assembled in the same manner as in Example 1, and the carbon dioxide electrolysis performance was investigated. Unlike in Example 1, the uneven surface 291 formed on the surface 28a of the flow path plate had a surface roughness of 0.02 μm or less, with an average roughness of approximately 0.01 to 0.05 μm. After 320 hours, salt precipitated in the flow path, causing blockage, making it impossible to continue the reaction.

[0120] Table 1 shows the collected cell voltages, the faradaic efficiency of CO (FE(CO)), and the faradaic efficiency of H2 (FE(H2)) in Examples 1, 2, 3, and 4, and Comparative Example 1.

[0121] [Table 1]

[0122] The results of Examples 1, 2, 3, and 4 and Comparative Example 1 show that by forming the uneven surface 291 and further supporting a cathode catalyst on the uneven surface 291, it is possible to suppress the decrease in the faradaic efficiency of CO even when the electrolysis reaction is carried out for a long period of time, and thus it is possible to suppress the decrease in cell performance.

[0123] The configurations of the above-described embodiments can be applied in combination with each other, and some of them can be replaced with other configurations. Although several embodiments of the present invention have been described herein, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0124] The above embodiments can be summarized in the following technical solutions. (Technical proposal 1) an anode; a cathode; a first flow path plate provided facing the anode and having a first recess that forms an anode flow path through which a first liquid flows; a second flow path plate provided facing the cathode and having a second recess that forms a cathode flow path through which the first gas flows; a separator disposed between the anode and the cathode; an electrolysis cell comprising: the second flow path plate has an uneven surface on the inner surface of the second recess, The electrolysis device, wherein the arithmetic mean roughness of the uneven surface is 0.03 μm or more and 50 μm or less. (Technical proposal 2) the anode oxidizes water contained in the first liquid to produce oxygen; The electrolysis device according to Technical Solution 1, wherein the cathode reduces carbon dioxide contained in the gas of Technical Solution 1 to produce carbon compounds. (Technical proposal 3) the anode oxidizes water contained in the first liquid to produce oxygen; The electrolysis device according to Technical Solution 1, wherein the cathode reduces nitrogen contained in the first gas to produce ammonia. (Technical proposal 4) The electrolysis device according to any one of Technical Schemes 1 to 3, wherein the second flow path plate has a first cathode catalyst layer including a first cathode catalyst provided on the uneven surface. (Technical proposal 5) The electrolysis device according to Technical Solution 4, wherein the amount of the first cathode catalyst is greater in the rear half of the cathode flow path than in the front half of the cathode flow path. (Technical proposal 6) the cathode has a second cathode catalyst layer containing a second cathode catalyst; The electrolysis device according to Technical Scheme 4 or 5, wherein the second cathode catalyst layer has a smaller amount of ionomer than the first cathode catalyst layer. (Technical proposal 7) the cathode has a second cathode catalyst layer containing a second cathode catalyst; The electrolysis device according to any one of Technical Schemes 4 to 6, wherein the density of the first cathode catalyst in the first cathode catalyst layer is lower than the density of the second cathode catalyst in the second cathode catalyst layer. (Technical proposal 8) The electrolysis device according to Technical Solution 7, wherein the density of the first cathode catalyst in the first cathode catalyst layer is 1 / 10 or less of the density of the second cathode catalyst in the second cathode catalyst layer. (Technical proposal 9) a gas-liquid separation unit that separates the first liquid from the first fluid discharged from the cathode flow path and has a first tank that stores the separated first liquid; a first flow path that connects an inlet and an outlet of the anode flow path and circulates the first liquid; a second tank provided in the first flow path and configured to contain the first liquid; a second flow path connecting the first tank and the first flow path; a first filter provided midway along the second flow path; The electrolysis device according to any one of Technical Schemes 1 to 8, further comprising: (Technical proposal 10) The electrolysis device according to Technical Solution 9 further comprises a third flow path connecting the first tank and the inlet of the cathode flow path. (Technical proposal 11) The electrolysis device according to Technical Solution 10, further comprising a humidifier connected to the third flow path. (Technical proposal 12) The electrolysis device according to Technical Solution 11, wherein the humidifier is connected to the first flow path. (Technical proposal 13) The electrolysis device according to any one of Technical Schemes 9 to 12, further comprising a second filter provided midway along the first flow path. (Technical proposal 14) The electrolysis device according to any one of Technical Schemes 1 to 13, wherein at least a portion of the surface of the cathode flow path is hydrophilic. [Explanation of symbols]

[0125] 1...electrolysis device, 10...anode portion, 11...anode, 11a...first surface, 11b...second surface, 12...anode flow path, 13...anode current collector plate, 14...flow path plate, 14a...land, 20...cathode portion, 21...cathode flow path, 22...cathode, 22A...gas diffusion layer, 22B...cathode catalyst layer, 22C...porous layer, 22a...first surface, 22b...second surface, 23...cathode flow path, 24...cathode current collector plate, 25...flow path plate, 26...land, 27...bridge portion, 28...Cathode flow path plate, 28a...surface, 29...land, 30...separator, 31...flow path, 32...flow path, 33...flow path, 40...power supply control unit, 100...anode solution supply system, 101...pressure control unit, 102...anode solution tank, 103...flow rate control unit, 104...reference electrode, 105...pressure gauge, 192...cathode catalyst, 200...cathode solution supply system, 201...pressure control unit, 202...cathode solution tank, 203...flow rate control unit, 204...reference electrode, 205... Pressure gauge, 206...gas component collection section, 280...hydrophilic region, 291...uneven surface, 292...cathode catalyst, 300...cathode gas supply system, 301...cathode gas supply source, 302...flow rate control section, 303...pressure gauge, 304...pressure control section, 311...humidifier, 400...product collection system, 401...gas-liquid separation section, 402...product collection section, 500...anode solution adjustment system, 501...valve, 502...filter, 600...waste liquid collection system, 601...waste liquid collection tank.

Claims

1. an anode; a cathode; a first flow path plate provided facing the anode and having a first recess forming an anode flow path through which a first liquid flows; a second flow path plate provided facing the cathode and having a second recess that forms a cathode flow path through which a first gas flows; a separator disposed between the anode and the cathode; an electrolysis cell comprising: the second flow path plate has an uneven surface on the inner surface of the second recess, the second flow path plate has a first cathode catalyst layer including a first cathode catalyst provided on the uneven surface; The electrolysis device, wherein the arithmetic mean roughness of the uneven surface is 0.03 μm or more and 50 μm or less.

2. the anode oxidizes water contained in the first liquid to produce oxygen; 2. The electrolysis device according to claim 1, wherein the cathode reduces carbon dioxide contained in the first gas to produce a carbon compound.

3. the anode oxidizes water contained in the first liquid to produce oxygen; The electrolysis device according to claim 1 , wherein the cathode reduces nitrogen contained in the first gas to produce ammonia.

4. The electrolysis device according to claim 1 , wherein a rear half of the cathode flow channel has a larger amount of the first cathode catalyst than a front half of the cathode flow channel.

5. the cathode has a second cathode catalyst layer containing a second cathode catalyst; The electrolysis device of claim 1 , wherein the second cathode catalyst layer has a lower amount of ionomer than the first cathode catalyst layer.

6. the cathode has a second cathode catalyst layer containing a second cathode catalyst; The electrolysis device according to claim 1 , wherein the density of the first cathode catalyst in the first cathode catalyst layer is lower than the density of the second cathode catalyst in the second cathode catalyst layer.

7. 7. The electrolysis device according to claim 6, wherein the density of the first cathode catalyst in the first cathode catalyst layer is 1 / 10 or less of the density of the second cathode catalyst in the second cathode catalyst layer.

8. a gas-liquid separation unit that separates the first liquid from the first fluid discharged from the cathode flow channel and has a first tank that accommodates the separated first liquid; a first flow path that connects an inlet and an outlet of the anode flow path and circulates the first liquid; a second tank provided in the first flow path and configured to contain the first liquid; a second flow path connecting the first tank and the first flow path; a first filter provided in the second flow path and configured to capture the first cathode catalyst separated through the cathode flow path; The electrolysis device of claim 1 further comprising:

9. 9. The electrolysis device according to claim 8, further comprising a third flow path connecting the first tank and the inlet of the cathode flow path.

10. 10. The electrolysis device of claim 9, further comprising a humidifier connected to the third flow path.

11. 11. The electrolysis device of claim 10, wherein the humidifier is connected to the first flow path.

12. 12. The electrolysis device according to claim 8, further comprising a second filter provided midway along the first flow path.

13. 12. The electrolysis device according to claim 1, wherein at least a portion of the surface of the cathode flow channel is hydrophilic.

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